Jonathan Lewis scored in the 84th minute to pull the Rapids into a 2-2 draw after Alan Pulido's penalty kick put Sporting up in the 72nd minute. The match was contentious, with two second-half red cards taking the Rapids down to nine players.
The Rapids took the early lead when Kellyn Acosta scored with the inside of his left foot in the sixth minute.
Colorado's Nicolas Benezet got a yellow card after an elbow to the face of Zusi, who was treated for several moments after the hit.
Minutes later, Shelton evened the game from a difficult angle with a shot that sailed into the top of the net and into the far corner.
A controversial handball call on Diego Rubio gave Pulido the penalty kick, which he buried to put Sporting up 2-1.
Just moments later, Colorado's Jack Price was sent off with another red card after it appeared he said something to the referee. That took the Rapids down to nine players, but Colorado appeared to overcome the disadvantage with Lewis' equalizer.
The two teams opened the regular season with a pair of victories before the season was suspended because of the coronavirus outbreak.
And both lost their opening matches in the MLS is Back tournament, which is being played without fans at ESPN's Wide World of Sports Complex.
Colorado fell 2-0 to Real Salt Lake. It was the first time the Rapids had failed to score since coach Robin Fraser took over last August.
Sporting lost a 2-1 heartbreaker to Minnesota United, giving up both goals in stoppage time.